The present invention relates to a CCD (Charge Coupled Device) image sensor including PN junction photosensor elements, more particularly, to an isolation structure between photosensor elements of a CCD image sensor.
Recently, a solid state image sensor has developed for use in a color video camera as disclosed in U.S. Pat. Application No. 216,759, filed on Dec. 15, 1980, by S. MIYATAKE, entitled "Intergrated CCD Image Sensor of the Interline Transfer Type". The U. K. counterpart was published on July 1, 1981 as GB No. 2,065,974 A. The German counterpart was published on Sept. 10, 1981 as DE-OS No. 3,047,216. The disclosure of this patent application is incorporated by reference.
The method of the solid state image sensor can be classified as XY address image sensor type and a CCD image sensor type. Particularly, the CCD image sensor has developed owing to the advantage of an S/N ratio (Signal Noise ratio) because the output capacity of the CCD image sensor is relatively small an interline transfer CCD image sensor including PN junction photodiodes shows a high sensitivity to blue light, and shows a high resolution to use a mosaic color filter.
Conventional CCD image sensor has required a complicated structure to improve the characteristics, so that a great number of masks are necessary and mask slippage may cause problems. Hence, the accuracy of the CCD may be deteriorated.